This invention relates to an improved chair in which the user may be seated in an upright or reclining position, and is particularly concerned with chairs of such nature containing confined volumes of water which impart supportive and cushioning effects.
Water-filled mattresses are generally well known and are frequently of rectangular shape having a depth of about 12 inches. In such mattresses, a thin-walled flexible plastic enclosure is utilized to confine a body of water. The plastic enclosure is supported from beneath by a flat floor or shelf, and at its sides by retaining walls. In this manner, the hydrostatic force generated by the depth of confined water does not distort or destroy the thin-walled enclosure, and a horizontally disposed upper surface is provided capable of supporting the user's weight.
The upper surface of a water-filled bed supports the user's weight primarily by virtue of the buoyant characteristic of a liquid which, when displaced exerts an upward force in accordance with the Archimedes principle of physics. The buoyancy effect, moderated by the effect of the film, creates a comfortable weight-bearing underlying support for the human body.
More conventional matress construction utilizing springs, flexible foams, fibrous batting, or combinations thereof support the user's weight essentially by their resilient characteristics acting in accordance with Hooke's law of physics. Their supportive properties are considerably different than those of water-filled mattresses and are highly dependent upon the characteristics of construction.
Chairs are generally fabricated employing the conventional supportive principles and components used in matress construction. In some instances, chairs have been made by confining air or a semi-fluid low density granular filling material such as dried beans or plastic foam. However, the use of liquid-filled chairs having supportive characteristics generally analagous to those of water-filled mattresses has not been disclosed heretofore.
Although securement of the comfort of the supportive characteristics of a water-filled mattress in a chair structure is a desirable goal, its actual achievement is made difficult by the inherent property of liquids to flow and to generate a hydrostatic pressure. Since a chair structure necessitates the arrangement of at least some structural member in substantially upright disposition, considerable hydrostatic pressure could be encountered. Such pressures would distort thin flexible films or rupture seams. If very strong, non-distorting films are utilized, the combined effect of the strong film and high retained pressure forms a turgid system having little capacity for deformation necessary for acceptable cushioning effect.
It is accordingly an object of the present invention to provide a chair containing water-filled cushioning members. It is a further object to provide a chair containing volumes of water confined in a manner to apply supportive and cushioning effects to the user's body. It is still another object of this invention to provide a chair containing a confined volume of water in substantially upright disposition and adapted to provide a cushioning effect without engendering high hydrostatic pressure. These and other objects and advantages of the invention will be apparent from the following description.